What do an abandoned coal mine and a nuclear power plant 75 miles
away have in common? The answer is water.

Generating electricity requires
a lot of water, about 25 gallons for each kilowatt-hour. The
most common thermal electric generating plants (fossil and nuclear)
are only about 35% efficient. What that means is a 1,000 megawatt
power plant has to dissipate over 2,800 megawatts in waste heat
to the environment. In world of thermodynamics it's called the
law of "there is no such thing as a free lunch." I
won't bore you with the details, so you'll have to push the "I
Believe button" and take my word for it.

There are two ways to get rid
of that heat. Engineers call them open-cycle or closed-cycle
cooling systems. An open-cycle system is simple. Find a nearby
river or lake, pump the water through the power plant's condensers,
and then send it back to its source.

A nuclear plant I once worked
at on the Mississippi River used an open-cycle cooling system.
Four pumps pulled one million gallons a minute out of the Big
Muddy, pushed it through the condenser, and discharged it right
back into the river. One million gallons a minute probably sounds
like a lot of water, but it was a drop in the bucket. The Mississippi
River carries about 288 million gallons per minute on a normal
day.

A closed-cycle cooling system
is one that does not draw water from the environment. The most
common system uses a cooling tower. The towers can use fans,
in which case they are called mechanical draft cooling towers,
or they can use the tendency of heated air to rise, in which
case they are called natural draft cooling towers. Those are
the hyperbolic towers that gained notoriety during the Three
Mile Island Accident in 1979. Natural draft towers are about
500 feet tall, made of concrete, and usually have a plume of
water vapor rising out their tops. The media always shows a
picture of a natural draft cooling tower whenever they want to
say something bad about nuclear power, and for some reason they
conveniently forget to explain that the cooling towers have absolutely
nothing to do with the nuclear reactor.

Some power plants use open-cycle
systems, but have built man-made reservoirs to absorb the heat
and minimize the effects on the microenvironment around the plant
site. I visited one in Texas recently that uses a 7,000 acre
"pond." It provides enough cooling water for two 1,200
megawatt nuclear power plants and has enough capacity for more.
A private reservoir has its advantages. Workers at the plant
have a catch-and-release fishing rodeo every year and pull red
fish out of reservoir that are as big as sharks.

Another option for open-cycle
plants is to use natural water sources but to augment them with
cooling towers, which reduces the temperature of the water going
back to the environment. This is usually required when the local
river commission places restrictions on the temperature of water
returning to the river.

These days, very few power
plants can be licensed for open-cycle cooling systems, and almost
all new plants are built with cooling towers. However, cooling
towers do not solve the problems associated with water consumption,
which is the water evaporated by the cooling tower. Water loves
to evaporate, and if you heat it, it evaporates more quickly.
A natural draft cooling tower can evaporate anywhere from 10,000
to 20,000 gallons of water a minute. If we couldn't provide
a source of makeup water, the cooling water system would eventually
lose enough water that the pumps wouldn't run. That makeup water
has to come from somewhere, and that's where plant designers
really begin to innovate.

For example, there is a nuclear
plant in Arizona that uses treated sewage water from Phoenix
as its makeup source. The treated water is pumped more than
50 miles through huge concrete pipes to the plant's reservoir
where it is used to provide makeup water for the plant's cooling
water systems. This has resulted in a symbiotic relationship
for both the city and the power station. It must be comforting
for Phoenix's residents to know that every time they flush their
toilets they are helping to generate their own electricity.

Over the past three years,
a nuclear power plant in eastern Pennsylvania has been demonstrating
another unique method for augmenting its cooling water needs.
The plant uses natural draft cooling towers, but relies on the
Schuylkill River (pronounced Sure Kill for you non-Pennsylvania
Dutch types) for its makeup needs. Efforts to improve the water
quality in the river resulted in restrictions on how much water
the plant could take out of the river. The plant's owners designed
and built a system to bring water from the Delaware River through
a series of pumping stations, reservoirs, and pipelines. At
full power, the plant's twin cooling towers need almost 30,000
gallons a minute for makeup.

It all came down to numbers.
Restrictions on using the Schuylkill applied whenever the river
temperature exceeded 59 degrees Fahrenheit and flow was below
a certain value. The intent was to prevent the river's dissolved
oxygen content from dropping below the value where aquatic life
begins to suffer. When those conditions were met, the plant
had to start the pumps on the Delaware River and bring in about
40 million gallons a day from the Delaware.

The Wadesville Pit

Necessity being the Mother
of Invention, the plant's owners embarked on an unconventional
way to bring additional water into the Schuylkill River and reduce
the need to pump water all the way from the Delaware. They found
the answer in the Anthracite Region, about 75 miles up the Schuylkill
in a little mining town called Wadesville, once the home of the
Wadesville Shaft and now the home of the Wadesville Pit.

As an underground mine, the
Wadesville Colliery ceased operations in 1930. When mining stopped,
the colliery owners allowed the mine to fill with water. In
1953, the Wadesville Pool was estimated to contain about 3.4
billion gallons of water. Strip mining began in 1940 and continued
off and on to the present. The open pit over the old Wadesville
workings is over 500 feet deep.

In 2003, the power plant owners
received permission to pump up to 10,000 gallons a minute from
the Wadesville Pool into the Schuylkill River, or about 40 percent
of the plant's makeup water needs. A recent extension allows
the plant to continue augmenting its water needs through 2007
with an increase to 12,000 gpm based on the minimal environmental
impact the mine water is having on the local aqua sphere. Unlike
most abandoned mine drainage, the Wadesville Pool is not acidic
and has a pH between 6 and 8 (pure water has a pH of 7).

The Wadesville Pool water takes
about four days to reach the power plant and it is monitored
daily. The augmentation period is only six months long, typically
when the Schuylkill is at low flows. The Wadesville Mine pool
recharges itself during the six months it is not being pumped,
so it is in effect a renewable resource. Another benefit of
the program is the plant's owners contribute money to the Schuylkill
River Restoration Fund based on the amount of water they do not
use from the Delaware. In 2005, there was a reduction of 2.63
billion gallons of water withdrawn from the Delaware River and
the plant contributed nearly $160,000 to the restoration fund.
That is an environmental plus if there ever was one.

Plans are on the horizon to
use more flooded and abandoned mines as cooling water sources
for power plants. The University of West Virginia has been conducting
research on the subject for a number of years. In those cases
where the mine pool is too acidic, it would be possible to use
it as a closed cooling system while leaving the water in the
mine and only using its relatively cool temperature to absorb
waste heat.

The Pennsylvania project is
a positive example of how technology and the environment can
exist in harmony and benefit both man and the ecosystem. Now
all we need to do is come up with a similar way for getting to
all that oil locked in the Green River oil shale!

Bob Ciminel's
articles may include satire and parody, and mix fact
with fiction.
He assumes informed readers will be able to tell the difference.
Bob lives in Roswell, Georgia, and works for the Institute
of Nuclear Power Operations. He is also a conductor
on the Blue Ridge Scenic Railway.
Contact Bob at ciminel@sitnews.us